Yes, NONNATIVE is a Scrabble word!

Letter values in Scrabble US: N 1, O 1, N 1, N 1, A 1, T 1, I 1, V 4, E 1.

Is it a valid word?

NONNATIVE is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

not being or composed of aborigines
of persons born in another area or country than that lived in
of plants or animals originating in a part of the world other than where they are growing

Also: foreign-born.